Those who are well-practised at letting people down while evading ferocious blame tend to be good at choosing their moments.

Boris Johnson seems to have pinpointed late afternoon on a Saturday as the optimum time to break bad news. One recalls his fraught unveiling of the second lockdown at the end of October last year as such an event. Perhaps there is something about this mid-point of a weekend which catches us at our most forgiving and phlegmatic.

The new restrictions the PM announced yesterday initially struck me as irritating but tolerable and not as bad as expected: back to compulsory masks in shops and on public transport but not in hospitality settings; tougher quarantine and testing requirements for international travellers and their contacts; a ramping up of the vaccine booster programme.

In the cold light of day, I’m not so sure. For our old foes the slippery slope and the boiled lobster are back on the scene. The first of these is the focus for the hyper-vigilant among us who will suspect that once the mindset of social control has been re-established among the powers-that-be, it will inevitably lead to a descent into ever more draconian measures. The latter is what happens to the less observant – a gradual turning up of the temperature that is barely perceptible at any given moment but ends with us noticing too late that our civil liberties have been boiled alive.

So perhaps we are better to cry foul and pledge resistance now rather than brace for the restoration of the rule of six in hospitality, then an instruction to work from home if we can, followed by limits on household mixing that could nix Christmas and finally the whole hog of another lockdown.

After all, one consequence of Mr Johnson’s announcements yesterday is the likely return of the “pingdemic” that wrecked so many plans in the spring and early summer. Being a contact of someone with the omicron variant will result in 10 precautionary days in the cooler. Another consequence is that short overseas breaks will once again become more trouble than they are worth, with isolating on arrival home a requirement until a negative PCR test result is obtained.

Yet another consequence will be the puncturing of a gradually emerging consensus among the populace that the worst is behind us and we can approach the future with a more positive attitude. If Franklin D Roosevelt’s famous observation that “the only thing we have to fear is fear itself” can properly be applied to current circumstances then Johnson has goofed by throwing the vehicle into reverse.

As Matt Ridley points out in the Telegraph today, lockdown measures come with a “severe psychological, economic and human cost” that is seldom accorded due weight by policymakers.

Yesterday’s Downing Street briefing included a review of the current Covid data by chief medical officer Professor Chris Whitty, giving him a chance to reprise his famous catchphrase “next slide please”. And this time round the slides told a positive story of falling hospitalisations and deaths even amid stubbornly high level of cases being detected. Basically, we’d cracked it.

Only now the story being pumped out on broadcast media is that omicron means we could be in big trouble again after all. Whitty’s fellow boffin, Sir Patrick Vallance, the chief scientific adviser, referred in passing at the briefing to the much better treatments that exist for Covid now, compared to a year ago.

Today’s Telegraph has further positive news on that score, with dramatic positive results from early trials of the “SpiDex” drug combination treatment and an equally exciting cell therapy being pioneered in Israel that seems to be bringing very sick people back from the brink of death.

Instead of contemplating this and taking further steps to restoring our collective sense of self-confidence, we have in effect been nudged back into our shells, just in case omicron proves so infectious and severe that it would send a huge surge of people into hospitals if we lived normally. That’s not what South African GP Dr Angelique Coetzee, the doctor who first spotted omicron, expects. She says the symptoms in patients she treated tended to be “mild” compared to those associated with previous strains of Covid.

We should all know a lot more in three weeks, when the current measures are reviewed in the light of what we have found out about omicron and any other relevant developments in the interim. Let us hope we are told it has been a false alarm – like many of the other variants have proved to be – rather than being put on the butcher’s slab for another round of civil liberties salami-slicing.

“I’m pretty confident to absolutely confident that this Christmas will be considerably better than last Christmas,” the Prime Minister told us yesterday. But didn’t he promise to save our Yuletide last year, only to pull the plug a few days out? So who is going to put much faith in his message this time round?